<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Title</title>
	<style type="text/less">
		.demo(){
			width:100px;
			height:200px;
			.my(){
				background:red;
			}
		}
		#one{
			//&:extend(.demo);
			.demo();
		}
		#two{
			//&:extend(.demo .my);
			.demo.my()
		}
	</style>
	<script src="lib/less.min.js"></script>
</head>
<body>
<div></div>
</body>
</html>